The decision tree model. The decision tree model learned from the consolidated results after applying the KDD process described in this work. The decision tree contains different parameters that were used in the data mining procedure: Concentration, Cell-type and time of exposure (24 h or 72 h). The outcome/end of each branch is either nontoxic (NT - the light grey squares) or Toxic (T – the dark grey squares). The numerical results are given below the outcome (NT or T) in the form of N/n1, where N represents all data results (NT or T) whereas n1 represents the number of data results which do not fulfill the outcome.